Imam as-Sadiq (‘a) said: "When it is the Day of Judgement, a group of people stand and then come to the door of Heaven to knock on it. They will be asked who they are and they will say: 'We are the people of patience.' Then, they will be inquired upon what they were patient about, and they will respond: 'We were patient with the obedience of Allah and were patient with avoiding the sins against Him'. So Allah, Almighty and Glorious, will say they are right and He will let them enter Heaven. This is the word of Allah, Almighty and Glorious, Who says: 'Those who patiently persevere will truly receive a reward without measure!'" (Sura 39. Verse 10)

Al-Kafi, vol. 2, p. 75

Imam Amir ul Mu'mineen ‘Ali (‘a) said: "Happy is he who has not great expectations and wishes (in his life) and tries to make the most of his remaining life-time."